GROTON, Conn. – The Navy’s newest attack submarine, the New Hampshire, was christened Saturday, delivered eight months ahead of schedule and $54 million under budget.

She’ll join the fleet this fall. She’s the fifth Virginia-class boat and the first Block II.

I believe that the biggest difference between Block I and Block II boats are the construction methods. I can’t seem to find much information about other improvements. The Block III (starting with SSN 784) will have an improved bow section with two “six-shooter” launch tubes rather than the current 12 tubes.

The plan had been for about 30 boats in the class. Here’s a ship list on Global Security that seems more or less up to date. These subs are always major topics of debate in the annual budget plan, and build rates are always jockeyed around each year while arguing about fleet size, so my guess would be that any similarities between original plans, today’s plans, and the final reality will be mere coincidence.